Disk drive

ABSTRACT

A disk drive includes a case having an outer surface, a recording medium and a magnetic head disposed inside the case, a board disposed outside the case and is electrically connected to the magnetic head, an electronic component mounted on a mounting surface of the board that faces the outer surface, and a heat conduction member having a hole and compressed between the electronic component and the outer surface in a thickness direction of the disk drive to thermally couple the electronic component to the case.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2020-040798, filed Mar. 10, 2020, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a disk drive.

BACKGROUND

Disk drives, such as hard disk drives (HDDs), include a magnetic disk, amagnetic head for reading and writing information from and to themagnetic disk, and a board mounted with various kinds of electroniccomponents. The electronic components, which generate heat, arethermally coupled to a heat sink or a case of an HDD so as to be cooled.

Electronic components may be thermally coupled to a case via a heatconductive member. The heat conductive member is compressed, forexample, between an electronic component and a wall of the case, andapplies reaction forces to the electronic component and a board on whichthe electronic component is mounted. The reaction forces increase asdeformability of the heat conductive member decreases.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an example of a hard disk drive(HDD) according to a first embodiment.

FIG. 2 is a sectional view schematically showing a part of the HDD ofthe first embodiment.

FIG. 3 is an exploded perspective view of a bottom wall, a controller,and a heat dissipation sheet in the HDD according to the firstembodiment.

FIG. 4 is a plan view schematically showing a bottom wall, a controller,and a heat dissipation sheet in an HDD according to a modificationexample of the first embodiment.

FIG. 5 is an exploded perspective view of a bottom wall, a controller,and a heat dissipation sheet in an HDD according to a second embodiment.

FIG. 6 is a perspective view schematically showing a heat dissipationsheet in an HDD according to a third embodiment.

FIG. 7 is a plan view schematically showing a bottom wall, a controller,and a heat dissipation sheet in an HDD according to a first modificationexample of the third embodiment.

FIG. 8 is a plan view schematically showing a bottom wall, a controller,and a heat dissipation sheet in an HDD according to a secondmodification example of the third embodiment.

DETAILED DESCRIPTION

Embodiments provide a disk drive including a heat conduction member thatapplies relatively small reaction forces to electronic components and aboard on which the electronic components are mounted.

In general, according to one embodiment, a disk drive includes a case, arecording medium, a magnetic head, a board, an electronic component, anda heat conduction member. The case has an outer surface. The recordingmedium is disposed inside the case and has a recording layer. Themagnetic head is disposed inside the case and is configured to read andwrite information from and to the recording medium. The board isdisposed outside the case, has a mounting surface that faces the outsidesurface, and is electrically connected to the magnetic head. Theelectronic component is mounted on the mounting surface. The heatconduction member includes a hole and is compressed between theelectronic component and the outer surface in a thickness direction ofthe disk drive to thermally couple the electronic component to the case.

First Embodiment

Hereinafter, a first embodiment will be described with reference toFIGS. 1 to 3. In the present specification, elements according toembodiments and description of the elements may be described usingseveral different expressions. The elements and the description of theelements are given by way of examples and are not limited to theexpressions used in the present specification. The elements may beidentified by terms different from those used in the presentspecification. In addition, the elements may be described usingexpressions different from those in the present specification.

FIG. 1 is a perspective view showing an example of a hard disk drive(HDD) 10 according to the first embodiment. The HDD 10 is an example ofa disk drive and may also be called an “electronic device”, a “storagedevice”, an “external storage device”, or a “magnetic disk drive”.

As shown in each drawing, an X-axis, a Y-axis, and a Z-axis are definedfor convenience in the present specification. The X-axis, the Y-axis,and the Z-axis are orthogonal to each other. The X-axis is defined alongthe width of the HDD 10. The Y-axis is defined along the length of theHDD 10. The Z-axis is defined along the thickness of the HDD 10.

An X direction, a Y direction, and a Z direction are defined in thepresent specification. The X direction is along the X-axis and includesa +X direction, which is indicated by the arrow of the X-axis, and a −Xdirection, which is an opposite direction of the arrow of the X-axis.

The Y direction is along the Y-axis and includes a +Y direction, whichis indicated by the arrow of the Y-axis, and a −Y direction, which is anopposite direction of the arrow of the Y-axis. The Z direction is alongthe Z-axis and includes a +Z direction, which is indicated by the arrowof the Z-axis, and a −Z direction, which is an opposite direction of thearrow of the Z-axis.

The HDD 10 includes a case 11, multiple magnetic disks 12, a spindlemotor 13, a clamp spring 14, multiple magnetic heads 15, an actuatorassembly 16, a voice coil motor (VCM) 17, a ramp load mechanism 18, anda flexible printed circuit (FPC) board 19. The magnetic disk 12 is anexample of a recording medium.

The case 11 includes a base 21, an inner cover 22, and an outer cover23. The base 21 is a closed-bottom container and includes a bottom wall25 and a side wall 26. The bottom wall 25 may also be called, forexample, a “wall” or a “plate”.

The bottom wall 25 is formed into an approximately rectangular or squareplate shape. The side wall 26 protrudes upwards from an edge of thebottom wall 25. The bottom wall 25 and the side wall 26 are made of, forexample, a metal material such as aluminum alloy, and are formed intoone body.

The inner cover 22 and the outer cover 23 are made of, for example, ametal material such as aluminum alloy. The inner cover 22 is attached toan end part of the side wall 26 by, for example, screws. The outer cover23 covers the inner cover 22 and is air-tightly fixed to an end part ofthe side wall 26 by, for example, welding.

The case 11 is sealed. The case 11 contains the magnetic disks 12, thespindle motor 13, the clamp spring 14, the magnetic heads 15, theactuator assembly 16, the voice coil motor 17, the ramp load mechanism18, and the FPC 19.

A vent hole 22 a is provided in the inner cover 22. A vent hole 23 a isprovided in the outer cover 23. After components are mounted inside thebase 21, and the inner cover 22 and the outer cover 23 are attached tothe base 21, air in the case 11 is evacuated through the vent holes 22 aand 23 a. Then, gas that is different from ambient air is injected intothe case 11.

The gas to be injected into the case 11 is, e.g., low-density gas havinga density lower than that of the air, or an inert gas having lowreactivity. In one example, helium is injected into the case 11.Alternatively, other fluid(s) may be injected into the case 11. Inanother example, the inside of the case 11 may be maintained at vacuum,a low pressure close to vacuum, or a negative pressure relative to theatmospheric pressure.

The vent hole 23 a of the outer cover 23 is closed by a seal 28. Theseal 28 air-tightly closes the vent hole 23 a to prevent the fluid,which is injected into the case 11, from leaking from the vent hole 23a.

The magnetic disk 12 includes, for example, a magnetic recording layerprovided on at least one of an upper surface and a lower surface. Thediameter of the magnetic disk 12 is, for example, 3.5 inches, but is notlimited to this.

The spindle motor 13 supports and rotates the multiple magnetic disks 12that are stacked via spaces. The clamp spring 14 retains the multiplemagnetic disks 12 to a hub of the spindle motor 13.

The magnetic head 15 records and reproduces information on and from therecording layer of the magnetic disk 12. In other words, the magnetichead 15 reads and writes information from and to the magnetic disk 12.The magnetic head 15 is supported by the actuator assembly 16.

The actuator assembly 16 is rotatably supported by a support shaft 31that is disposed at a position separated from the magnetic disk 12. Thevoice coil motor 17 rotates the actuator assembly 16 and moves theactuator assembly 16 to a desired position. The voice coil motor 17rotates the actuator assembly 16 to make the magnetic head 15 move tothe outermost circumference of the magnetic disk 12. In response tothis, the ramp load mechanism 18 holds the magnetic head 15 at anunloading position separated from the magnetic disk 12.

The actuator assembly 16 includes an actuator block 35, multiple arms36, and multiple head suspension assemblies 37. The head suspensionassembly 37 may also be called a “head gimbal assembly (HGA)” in somecontexts.

The actuator block 35 is rotatably supported by the support shaft 31via, for example, a bearing. The multiple arms 36 protrude in adirection approximately orthogonal to the support shaft 31 from theactuator block 35. Alternatively, the actuator assembly 16 may bedisassembled, and the multiple arms 36 may respectively protrude frommultiple actuator blocks 35.

The multiple arms 36 are arranged via spaces in the extending directionof the support shaft 31. Each of the arms 36 is formed into a plateshape that allows the arm 36 to enter the spaces between adjacentmagnetic disks 12. The multiple arms 36 extend approximately parallel toeach other.

The actuator block 35 and the multiple arms 36 are formed into one bodyby using, for example, aluminum. The materials for the actuator block 35and the arm 36 are not limited to this example.

A voice coil of the voice coil motor 17 is provided at a protrusion thatprotrudes from the actuator block 35. The voice coil motor 17 includes apair of yokes, the voice coil interposed between the yokes, and magnetsprovided in the yokes.

The head suspension assembly 37 is attached at an end part of acorresponding arm 36 and protrudes from the arm 36. Thus, the multiplehead suspension assemblies 37 are arranged via spaces in the extendingdirection of the support shaft 31.

Each of the multiple head suspension assemblies 37 includes a base plate41, a load beam 42, and a flexure 43. In addition, the magnetic head 15is attached to the head suspension assembly 37.

The base plate 41 and the load beam 42 are made of, for example,stainless steel. The materials for the base plate 41 and the load beam42 are not limited to this example. The base plate 41 is formed into aplate shape and is attached at an end part of the arm 36. The load beam42 is formed into a plate shape that is thinner than the base plate 41.The load beam 42 is attached at an end part of the base plate 41 andprotrudes from the base plate 41.

The flexure 43 is formed into a long narrow strip shape. The shape ofthe flexure 43 is not limited to this example. The flexure 43 is astacked plate including a metal plate as a backing layer, an insulatinglayer, a conductive layer, and a protective layer as an insulatinglayer. The metal plate is made of stainless or other material. Theinsulating layer is formed on the metal plate. The conductive layer isformed on the insulating layer and includes multiple wirings or wiringpatterns. The protective layer covers the conductive layer.

One end of the flexure 43 is provided with a gimbal part or an elasticsupport. The gimbal part is positioned on the load beam 42 and isdisplaceable. The magnetic head 15 is mounted on the gimbal part. Theother end of the flexure 43 is coupled to the FPC 19. Thus, the FPC 19is electrically connected to the magnetic head 15 via the wiring of theflexure 43.

FIG. 2 is a sectional view schematically showing a part of the HDD 10 ofthe first embodiment. As shown in FIGS. 1 and 2, the HDD 10 furtherincludes a printed circuit board (PCB) 51, an interface (I/F) connector52, multiple electronic components 53, a relay connector 54, andmultiple screws 55. The PCB 51 is an example of a board. The screw 55 isan example of a mounting member.

The PCB 51 is, for example, a rigid board, such as a glass epoxy board,and the PCB 51 is, e.g., a multilayered board or a build-up board. Asshown in FIG. 2, the PCB 51 is disposed outside the case 11 and ismounted at an outside part of the bottom wall 25 of the base 21.

The PCB 51 is mounted to the bottom wall 25 by the multiple screws 55.The mounting member may be some other member such as a hook for mountingthe PCB 51 to the bottom wall 25 by snap-fit.

The I/F connector 52 in FIG. 1 is in conformity with an interfacestandard such as Serial ATA and is coupled to an I/F connector of a hostcomputer. The HDD 10 is supplied with power from the host computer viathe I/F connector 52 and transceives various kinds of data with the hostcomputer.

The multiple electronic components 53 include a controller 58. Themultiple electronic components 53 may include, for example, a servocontroller for driving the spindle motor 13 and the VCM 17, variouskinds of memories, such as a RAM, a ROM, and a buffer memory, and otherelectronic components such as a coil and a capacitor.

The controller 58 is, for example, an integrated circuit (e.g., alarge-scale integration, LSI circuit), and includes a read/write channel(RWC), a hard disk controller (HDC), and a processor. The RWC, the HDC,and the processor may be separate components.

The processor of the controller 58 is, for example, a central processingunit (CPU). The processor controls the entire HDD 10 in accordance with,e.g., firmware that is preliminarily stored in a ROM and the magneticdisk 12. In one example, the processor loads the firmware in the ROM andthe magnetic disk 12 to a RAM and executes control of the magnetic head15, the RWC, the HDC, and other components in accordance with the loadedfirmware.

The relay connector 54 is electrically connected to various kinds ofcomponents that are arranged inside the case 11, via, for example, aconnector provided in the bottom wall 25. Thus, the PCB 51 iselectrically connected to the spindle motor 13, the magnetic head 15,the actuator assembly 16, the VCM 17, and the FPC 19, which are arrangedinside the case 11, through the relay connector 54.

As shown in FIG. 2, the bottom wall 25 of the case 11 includes an insidesurface 25 a and an outside surface 25 b. The inside surface 25 a isformed approximately flat and faces the inside of the case 11. Theoutside surface 25 b is positioned on a side opposite to the insidesurface 25 a. The outside surface 25 b is formed approximately flat andfaces the outside of the case 11. In addition, the outside surface 25 bfaces the PCB 51 via a space. The inside surface 25 a and the outsidesurface 25 b are approximately parallel to each other and extend on anX-Y plane. In FIG. 2, the inside surface 25 a faces the −Z direction,whereas the outside surface 25 b faces the +Z direction.

The PCB 51 includes a mounting surface 51 a. The mounting surface 51 ais formed into approximately flat and faces the outside surface 25 b ofthe bottom wall 25 via a space. In FIG. 2, the mounting surface 51 afaces the −Z direction. The mounting surface 51 a is mounted with themultiple electronic components 53, including the controller 58. Thus,the controller 58 is positioned between the outside surface 25 b of thebottom wall 25 and the mounting surface 51 a of the PCB 51. At least oneof the multiple electronic components 53 may be mounted on a part thatis different from the mounting surface 51 a of the PCB 51.

The controller 58 includes a first surface 58 a and a second surface 58b. The second surface 58 b is an example of a facing surface. The firstsurface 58 a faces the mounting surface 51 a of the PCB 51. The firstsurface 58 a may be provided with a terminal. The first surface 58 a maybe in contact with the mounting surface 51 a or may be separated fromthe mounting surface 51 a. The second surface 58 b is positioned on aside opposite to the first surface 58 a. The second surface 58 b facesthe outside surface 25 b of the bottom wall 25 via a space. In FIG. 2,the first surface 58 a faces the +Z direction, whereas the secondsurface 58 b faces the −Z direction.

The HDD 10 further includes a heat dissipation sheet 61. The heatdissipation sheet 61 is an example of a heat conduction member. The heatdissipation sheet 61 is made of, for example, synthetic resin with highthermal conductivity, such as acrylic rubber. Alternatively, the heatdissipation sheet 61 may be made of other material. The thermalconductivity of the heat dissipation sheet 61 is at least higher thanthat of the air.

FIG. 3 is an exploded perspective view of the bottom wall 25, thecontroller 58, and the heat dissipation sheet 61 of the firstembodiment. As shown in FIG. 3, the heat dissipation sheet 61 is formedinto, for example, an approximately rectangular parallelepiped shape.The shape of the heat dissipation sheet 61 is not limited to thisexample.

As shown in FIG. 2, the heat dissipation sheet 61 includes a surface 62.The surface 62 is an outside surface facing the outside of the heatdissipation sheet 61. The surface 62 includes a first contact surface65, a second contact surface 66, and a side surface 67. The secondcontact surface 66 is an example of each of a second contact surface anda contact surface.

The first contact surface 65 faces and is in contact with the secondsurface 58 b of the controller 58. In FIG. 2, the first contact surface65 is an end surface in the +Z direction of the heat dissipation sheet61 and faces the +Z direction. The first contact surface 65 has, forexample, adhesiveness, and is affixed to the second surface 58 b. Thefirst contact surface 65 is not limited by this example.

The second contact surface 66 is positioned on a side opposite to thefirst contact surface 65. The second contact surface 66 faces and is incontact with the outside surface 25 b of the bottom wall 25. In FIG. 2,the second contact surface 66 is an end surface in the −Z direction ofthe heat dissipation sheet 61 and faces the −Z direction. The secondcontact surface 66 has, for example, adhesiveness, and is affixed to theoutside surface 25 b. The second contact surface 66 is not limited bythis example.

The heat dissipation sheet 61, which is in contact with the secondsurface 58 b of the controller 58 and the outside surface 25 b of thebottom wall 25, thermally couples the controller 58 to the bottom wall25 of the case 11. This allows conduction of heat between the controller58 and the bottom wall 25 of the case 11 via the heat dissipation sheet61. The controller 58 generates heat, for example, when arithmeticoperations are executed therein. The heat that is generated from thecontroller 58 is conducted to the bottom wall 25 through the heatdissipation sheet 61. As a result, the controller 58 loses heat and iscooled. Another member may thermally couple the controller 58 to theheat dissipation sheet 61, or yet another member may thermally couplethe heat dissipation sheet 61 to the bottom wall 25 of the case 11.Basically, the heat dissipation sheet 61 is provided in a path forconducting heat between the controller 58 and the bottom wall 25 of thecase 11; however, the heat dissipation sheet 61 may be separated from atleast one of the controller 58 and the bottom wall 25 of the case 11.

As shown in FIG. 3, when viewed in the Z direction, the heat dissipationsheet 61 is smaller than the controller 58. Thus, each of the firstcontact surface 65 and the second contact surface 66 is smaller than thefirst surface 58 a and the second surface 58 b of the controller 58.Alternatively, the heat dissipation sheet 61 may have dimensions thatare the same as or larger than the dimensions of the controller 58 whenviewed from the Z direction.

The side surface 67 is provided between the first contact surface 65 andthe second contact surface 66. In FIG. 2, the side surface 67 facesapproximately the X direction or the Y direction. In other words, theside surface 67 faces a direction along the outside surface 25 b of thebottom wall 25, which is a direction approximately parallel to theoutside surface 25 b.

As shown in FIG. 3, the heat dissipation sheet 61 is provided with holes71. The holes 71 include multiple through holes 72 in the firstembodiment. The through hole 72 extends approximately in the Z directionand penetrates through the heat dissipation sheet 61 between the firstcontact surface 65 and the second contact surface 66. Thus, the throughhole 72 opens at the first contact surface 65 and the second contactsurface 66. The through hole 72 may extend in another direction.

The multiple through holes 72 include a first through hole 72A and asecond through hole 72B. The first through hole 72A is larger than thesecond through hole 72B. Specifically, a cross sectional area orthogonalto the Z direction of the first through hole 72A is larger than that ofthe second through hole 72B. In addition, an inner circumferentiallength of the cross-section of the first through hole 72A takenorthogonal to the Z direction is longer than that of the second throughhole 72B.

As shown in FIG. 2, the first through hole 72A is closer to the screw 55than the second through hole 72B. Specifically, a distance L1 betweenthe first through hole 72A and a screw 55 closest to the first throughhole 72A is shorter than a distance L2 between the second through hole72B and a screw 55 closest to the second through hole 72B.

The first through hole 72A, which is larger than the second through hole72B, is provided closer to the screw 55 than the second through hole72B. That is, the hole 71 that is closer to the screw 55 is larger inthe heat dissipation sheet 61. The hole 71 is not limited by the exampledescried above. In one example, the width of the hole 71 may beincreased as the hole 71 is closer to the screw 55.

The multiple through holes 72 each have a polygonal cross sectionorthogonal to the Z direction in the first embodiment. The polygonalshape is a square shape, for example. Alternatively, the polygonal shapeis not limited to this example and may be a triangular, pentagonal, orother polygonal shape.

The heat dissipation sheet 61 further includes an inside surface 75 thatforms the through hole 72. The inside surface 75 faces the inside of thethrough hole 72 in the direction along the outside surface 25 b of thebottom wall 25. In FIG. 2, the inside surface 75 faces approximately theX direction or the Y direction. A part of the inside surface 75 andanother part of the inside surface 75 face each other.

The heat dissipation sheet 61 is compressed between the second surface58 b of the controller 58 and the outside surface 25 b of the bottomwall 25. Specifically, in a natural state in which the heat dissipationsheet 61 is not compressed between the second surface 58 b of thecontroller 58 and the outside surface 25 b of the bottom wall 25, thethickness of the heat dissipation sheet 61 is greater than a distancebetween the second surface 58 b of the controller 58 and the outsidesurface 25 b of the bottom wall 25. The thickness of the heatdissipation sheet 61 is defined by the distance between the firstcontact surface 65 and the second contact surface 66. FIG. 2 shows aheat dissipation sheet 61 in the natural state by a two-dot chain linein a virtual manner and also shows a compressed heat dissipation sheet61 by a solid line.

The compressed heat dissipation sheet 61 is deformed between the secondsurface 58 b of the controller 58 and the outside surface 25 b of thebottom wall 25 and extends in the direction along the outside surface 25b. In other words, the compressed heat dissipation sheet 61 extends in adirection orthogonal to the Z direction, in which the second surface 58b and the outside surface 25 b face each other, between the secondsurface 58 b of the controller 58 and the outside surface 25 b of thebottom wall 25. The heat dissipation sheet 61 may be elasticallydeformed or may be plastically deformed. In this embodiment, forexample, the compressed heat dissipation sheet 61 is elasticallyrestored to a shape close to the shape before it is compressed, to someextent, upon being released from compression. The compressed heatdissipation sheet 61 may be elastically restored to the shape before itwas compressed or may remain having a compressed shape upon beingreleased from compression.

The heat dissipation sheet 61 that is compressed in the Z directionflows in such a manner as to extend in the X-Y plane. Specifically, apart of the heat dissipation sheet 61 is protruded from the side surface67 toward the outside of the heat dissipation sheet 61. This results inmovement of the side surface 67 toward the outside of the heatdissipation sheet 61. Moreover, another part of the heat dissipationsheet 61 is protruded from the inside surface 75 toward the inside ofthe heat dissipation sheet 61. This results in movement of the insidesurface 75 toward the inside of the heat dissipation sheet 61, whereby across section orthogonal to the Z direction of the hole 71 is reduced.Additionally, the inside surfaces 75 may be brought into contact witheach other and may close the hole 71.

The extension of the compressed heat dissipation sheet 61 makes thefirst contact surface 65 and the second contact surface 66 larger thanthe first contact surface 65 and the second contact surface 66 of theheat dissipation sheet 61 in the natural state. That is, in accordancewith compression of the heat dissipation sheet 61, the contact areabetween the heat dissipation sheet 61 and the controller 58 increases,and the contact area between the heat dissipation sheet 61 and thebottom wall 25 increases.

As shown in FIG. 3, the outside surface 25 b of the bottom wall 25includes a coated part 81 and an exposed part 82. FIG. 3 shows thecoated part 81 by hatching, for convenience of description. The coatedpart 81 is a part of the metal bottom wall 25 that is coated with apaint 85. The paint 85 is, for example, an insulating paint. The thermalconductivity of the paint 85 is lower than that of the metal bottom wall25. The exposed part 82 is a part at which metal of the bottom wall 25is exposed while being enclosed by the coated part 81.

As shown in FIG. 2, for example, the bottom wall 25 further includes abottom surface 25 c and multiple protrusions 88. The bottom surface 25 cis positioned on a side opposite to the inside surface 25 a and facesthe outside of the case 11. The bottom surface 25 c is closer to theinside surface 25 a than the outside surface 25 b. The protrusion 88protrudes from the bottom surface 25 c.

The bottom surface 25 c is covered with the paint 85, and an end surfaceof the protrusion 88 is exposed without being covered with the paint 85.Thus, the paint 85 provides the coated part 81 that is a part of theoutside surface 25 b, and the protrusion 88 forms the exposed part 82that is the other part of the outside surface 25 b. The coated part 81and the exposed part 82 are not limited by these examples.

As shown in FIG. 3, the exposed part 82 of the first embodiment includesa first exposed part 91 and a second exposed part 92. The first exposedpart 91 has approximately the same shape as the second contact surface66 of the heat dissipation sheet 61 in the natural state. Specifically,the first exposed part 91 is formed into an approximately square shapewith the same dimensions as or slightly larger than the second contactsurface 66 of the heat dissipation sheet 61 in the natural state. Thesecond exposed part 92 is formed into an approximately square frameshape enclosing the first exposed part 91 with an interval therebetween.The coated part 81 is provided between the first exposed part 91 and thesecond exposed part 92.

The second contact surface 66 of the heat dissipation sheet 61 in thenatural state is in contact with and is affixed to the first exposedpart 91. The first exposed part 91 is used for positioning the heatdissipation sheet 61. For this purpose, an edge 91 a of the firstexposed part 91 extends along an outside edge 66 a of the second contactsurface 66 of the heat dissipation sheet 61 in the natural state. Theedge 91 a is an example of a first edge.

The outside edge 66 a of the second contact surface 66 forms an outercircumference of the second contact surface 66. The second contactsurface 66 includes multiple inside edges that form open ends of themultiple through holes 72. The inside edge and the outside edge 66 a areseparated from each other in this embodiment.

Each of the edge 91 a of the first exposed part 91 and the outside edge66 a of the second contact surface 66 of the heat dissipation sheet 61in the natural state is formed into an approximately square shape. Theoutside edge 66 a is overlaid on the edge 91 a or is positioned on thefirst exposed part 91 slightly separately from the edge 91 a. Theoutside edge 66 a and the edge 91 a extend approximately parallel toeach other. The extending direction of the edge 91 a and the extendingdirection of the outside edge 66 a may be slightly different from eachother.

The second exposed part 92 includes an inside edge 92 a and an outsideedge 92 b. The outside edge 92 b is an example of a second edge. Theinside edge 92 a forms an inner circumference of the second exposed part92 and is in contact with the coated part 81 between the first exposedpart 91 and the second exposed part 92. The outside edge 92 b forms anouter circumference of the second exposed part 92 and is in contact withthe coated part 81 enclosing the second exposed part 92.

The second exposed part 92 is separated from the heat dissipation sheet61 that is affixed to the first exposed part 91 and that is in thenatural state. Thus, the inside edge 92 a and the outside edge 92 b ofthe second exposed part are more separated from the outside edge 66 a ofthe second contact surface 66 of the heat dissipation sheet 61 in thenatural state than the edge 91 a of the first exposed part 91.

As shown in FIG. 2, the heat dissipation sheet 61 is compressed betweenthe second surface 58 b of the controller 58 and the outside surface 25b of the bottom wall 25 and extends in the direction along the outsidesurface 25 b, as described above. As a result, the compressed heatdissipation sheet 61 crosses over the coated part 81, which encloses thefirst exposed part 91, and is brought into contact with the secondexposed part 92.

The outside edge 92 b of the second exposed part 92 has approximatelythe same shape as the outside edge 66 a of the second contact surface 66of the compressed heat dissipation sheet 61. Thus, the outside edge 92 bof the second exposed part 92 extends along the outside edge 66 a of thesecond contact surface 66 of the heat dissipation sheet 61 that is inthe condition of being compressed between the second surface 58 b of thecontroller 58 and the outside surface 25 b of the bottom wall 25.

The outside edge 66 a of the second contact surface 66 is overlaid onthe outside edge 92 b of the second exposed part 92 or is positioned onthe second exposed part 92 slightly separately from the outside edge 92b. The outside edge 66 a and the outside edge 92 b extend approximatelyparallel to each other. The extending direction of the outside edge 92 band the extending direction of the outside edge 66 a may be slightlydifferent from each other.

As described above, the heat dissipation sheet 61 is positioned by thefirst exposed part 91 and is affixed thereto in assembling. In responseto mounting the PCB 51, which is mounted with the controller 58, to thebottom wall 25, the heat dissipation sheet 61 is compressed between thesecond surface 58 b of the controller 58 and the outside surface 25 b ofthe bottom wall 25. The heat dissipation sheet 61 that is extended bycompression comes into contact with the second exposed part 92 as wellas the first exposed part 91. This improves efficiency of heatconduction between the heat dissipation sheet 61 and the bottom wall 25.

In the HDD 10 according to the first embodiment described above, theheat dissipation sheet 61 is compressed between the controller 58 andthe outside surface 25 b of the case 11 and thermally couples thecontroller 58 to the case 11. The compressed heat dissipation sheet 61is deformed and extends in the direction along the outside surface 25 bof the case 11 between the controller 58 and the case 11. The heatdissipation sheet 61 is provided with the hole 71. In response tocompression of the heat dissipation sheet 61, an outside edge part ofthe heat dissipation sheet 61, including the side surface 67, isprotruded outwardly, and an inside edge part of the heat dissipationsheet 61, including the inside surface 75 for forming the hole 71, isprotruded inwardly. In this case, parts that are able to be deformed andbe extended increase in the heat dissipation sheet 61, compared with acase of not providing the hole 71. Thus, the compressed heat dissipationsheet 61 is more easily deformed, and this reduces the reaction forcesacting from the compressed heat dissipation sheet 61 to the controller58 and the PCB 51 and to the case 11. When the reaction forces acting onthe controller 58 and the PCB 51 and on the case 11 are great, there arerisks that the PCB 51 and the bottom wall 25 of the case 11 are deformedin such a manner as to be warped and stress at a coupled part of thecontroller 58 and the PCB 51 increases. On the other hand, in the HDD 10of this embodiment, the reaction forces are reduced as described above,and this enables reducing deformation of the PCB 51 and the bottom wall25 of the case 11 as well as preventing increase in stress at thecoupled part of the controller 58 and the PCB 51.

The holes 71 include the through hole 72 that penetrates through theheat dissipation sheet 61. This structure enlarges the inside edge part,that is, the inside surface 75 of the heat dissipation sheet 61. Thus,the compressed heat dissipation sheet 61 is more easily deformed, andthis reduces the reaction forces acting from the compressed heatdissipation sheet 61 to the controller 58 and the PCB 51 and to the case11.

The heat dissipation sheet 61 includes the first contact surface 65 tobe in contact with the controller 58 and the second contact surface 66to be in contact with the outside surface 25 b. The through hole 72penetrates through the heat dissipation sheet 61 between the firstcontact surface 65 and the second contact surface 66. In this case, thereaction force acting from the first contact surface 65 to thecontroller 58 is better distributed at the first contact surface 65, andthe reaction force acting from the second contact surface 66 to theoutside surface 25 b is better distributed at the second contact surface66, compared with a case in which the through hole 72 penetrates throughthe heat dissipation sheet 61 in the direction along the outside surface25 b. Moreover, the heat dissipation sheet 61 that is provided with thehole 71 is easy to manufacture. In one example, multiple heatdissipation sheets 61 can be manufactured by cutting a larger sheet withmultiple holes 71 that are provided in approximately parallel to eachother.

The controller 58 includes the second surface 58 b that faces theoutside surface 25 b. The heat dissipation sheet 61 includes the firstcontact surface 65 to be in contact with the second surface 58 b and thesecond contact surface 66 to be in contact with the outside surface 25b. The first contact surface 65 is smaller than the second surface 58 b.In other words, for example, the heat dissipation sheet 61 is smallerthan the controller 58, and the outside edges of the heat dissipationsheet 61 are enclosed by the outside edges of the controller 58, whenviewed in the +Z direction along the Z direction from the outsidesurface 25 b to the mounting surface 51 a. The heat dissipation sheet 61is thus formed relatively small. The heat dissipation sheet 61 isgenerally more easily deformed as it is smaller. Thus, the compressedheat dissipation sheet 61 is more easily deformed, and this reduces thereaction forces acting from the compressed heat dissipation sheet 61 tothe controller 58 and the PCB 51 and to the case 11.

In this embodiment, the heat dissipation sheet 61 is provided with thehole 71, and therefore, the areas of the first contact surface 65 andthe second contact surface 66 are decreased compared with a case of notproviding the hole 71. However, the areas of the first contact surface65 and the second contact surface 66 are set in accordance with a setamount of heat to be conducted between the controller 58 and the case11. For this reason, in this embodiment in which the hole 71 isprovided, the areas of the first contact surface 65 and the secondcontact surface 66 are set to be large as much as possible in accordancewith the set amount of heat to be conducted. The first contact surface65 is smaller than the second surface 58 b of the controller 58. Thisprevents the first contact surface 65 from protruding out of the secondsurface 58 b of the controller 58 although the areas of the firstcontact surface 65 and the second contact surface 66 are set large.

The PCB 51 is mounted to the case 11 by the multiple screws 55. The heatdissipation sheet 61 is compressed between the controller 58 and theoutside surface 25 b. Thus, the PCB 51 is deformed by the reaction forceof the heat dissipation sheet 61, in such a manner as to be warped. Asthe controller 58 is closer to the screw 55, the distance between thecontroller 58 and the outside surface 25 b decreases, and a load actingon the heat dissipation sheet increases. In this embodiment, the hole 71that is closer to the screw 55 is larger in the heat dissipation sheet61. In these conditions, as the heat dissipation sheet 61 is closer tothe screw 55, the heat dissipation sheet 61 is more easily deformed, andthe reaction forces acting from the heat dissipation sheet 61 to thecontroller 58 and the PCB 51 and to the case 11 are reduced and arebetter distributed.

The hole 71 has a polygonal cross section. The outer circumference ofthe polygonal shape is longer than a circumference of a circle havingthe same area as the polygonal shape. For this reason, an inside edgepart of the heat dissipation sheet 61 can be set large compared with acase in which the hole 71 is circular, in the HDD 10 of this embodiment.Specifically, an outer circumference of a cross section orthogonal tothe Z direction of the hole 71 is made long. Thus, the compressed heatdissipation sheet 61 is more easily deformed, and this reduces thereaction forces acting from the compressed heat dissipation sheet 61 tothe controller 58 and the PCB 51 and to the case 11.

The outside surface 25 b includes the exposed part 82 at which the metalis exposed. The heat dissipation sheet 61 includes the second contactsurface 66 to be in contact with the exposed part 82. The edge 91 a ofthe first exposed part 91, which is included in the exposed part 82,extends along the outside edge 66 a of the second contact surface 66 ofthe heat dissipation sheet 61 that is in the condition of not beingcompressed between the controller 58 and the outside surface 25 b.Compared with the edge 91 a, the outside edge 92 b of the second exposedpart 92, which is included in the exposed part 82, is separated from theoutside edge 66 a of the second contact surface 66 of the heatdissipation sheet 61 that is in the condition of not being compressedbetween the controller 58 and the outside surface 25 b. Moreover, theoutside edge 92 b extends along the outside edge 66 a of the secondcontact surface 66 of the heat dissipation sheet 61 that is in thecondition of being compressed between the controller 58 and the outsidesurface 25 b. Attaching the heat dissipation sheet 61 to the case 11with reference to the edge 91 a enables a more exact arrangement of theheat dissipation sheet 61 at a desired position. Moreover, the heatdissipation sheet 61 that is extended by deformation is in contact withthe exposed part 82 by a larger contact area. This improves heatdissipation performance of the heat dissipation sheet 61 with respect tothe controller 58.

FIG. 4 is a plan view schematically showing the bottom wall 25, thecontroller 58, and the heat dissipation sheet according to amodification example of the first embodiment. FIG. 4 shows thecontroller 58 by a two-dot chain line in a virtual manner. As shown inFIG. 4, the cross section orthogonal to the Z direction of the throughhole 72 may be circular. In this case, the hole 71 can be easily formedby, for example, drilling with a drill or punching.

Second Embodiment

Hereinafter, a second embodiment will be described with reference toFIG. 5. In the following description of multiple embodiments, elementshaving functions similar to those of the already described elements aredenoted by the same reference signs as those of the already describedelements, and descriptions thereof may be omitted. In addition, multipleelements having the same reference signs may not have exactly the samefunctions and characteristics and may have different functions andcharacteristics in accordance with each embodiment.

FIG. 5 is an exploded perspective view of the bottom wall 25, thecontroller 58, and the heat dissipation sheet 61 according to the secondembodiment. As shown in FIG. 5, the exposed part 82 of the secondembodiment includes a third exposed part 101 and multiple fourth exposedparts 102 instead of the first exposed part 91 and the second exposedpart 92.

The third exposed part 101 has approximately the same shape as thesecond contact surface 66 of the heat dissipation sheet 61 in thenatural state. Specifically, the third exposed part 101 is formed intoan approximately square shape with the same dimensions as or slightlylarger than the second contact surface 66 of the heat dissipation sheet61 in the natural state.

The second contact surface 66 of the heat dissipation sheet 61 in thenatural state is in contact with and is affixed to the third exposedpart 101. That is, the third exposed part 101 is used for positioningthe heat dissipation sheet 61. For this purpose, an edge 101 a of thethird exposed part 101 extends along the outside edge 66 a of the secondcontact surface 66 of the heat dissipation sheet 61 in the naturalstate. The edge 101 a is an example of the first edge.

Each of the multiple fourth exposed parts 102 is formed into anapproximately square shape that is smaller than the third exposed part101. The fourth exposed part 102 is not limited by this example. Thefourth exposed part 102 is contiguous with the third exposed part 101and protrudes from the edge 101 a of the third exposed part 101. Inaddition, the multiple fourth exposed parts 102 are separated from eachother.

Each of the multiple fourth exposed parts 102 has an outside edge 102 a.The outside edge 102 a is an example of the second edge. The outsideedge 102 a extends approximately parallel to the edge 101 a of the thirdexposed part 101.

The fourth exposed part 102 is separated from the heat dissipation sheet61 that is affixed to the third exposed part 101 and that is in thenatural state. The outside edge 102 a of the fourth exposed part 102 ismore separated from the outside edge 66 a of the second contact surface66 of the heat dissipation sheet 61 in the natural state than the edge101 a of the third exposed part 101.

The outside edge 102 a of the fourth exposed part 102 has a shapecorresponding to the outside edge 66 a of the second contact surface 66of the compressed heat dissipation sheet 61. The outside edge 102 a ofthe fourth exposed part 102 extends along the outside edge 66 a of thesecond contact surface 66 of the heat dissipation sheet 61 that is inthe condition of being compressed between the second surface 58 b of thecontroller 58 and the outside surface 25 b of the bottom wall 25.

The heat dissipation sheet 61 is positioned by the third exposed part101 and is affixed thereto in assembling. In response to mounting thePCB 51, which is mounted with the controller 58, to the bottom wall 25,the heat dissipation sheet 61 is compressed between the second surface58 b of the controller 58 and the outside surface 25 b of the bottomwall 25. The heat dissipation sheet 61 that is extended by compressioncomes into contact with the multiple fourth exposed parts 102 as well asthe third exposed part 101. This improves efficiency of heat conductionbetween the heat dissipation sheet 61 and the bottom wall 25.

In the HDD 10 of the second embodiment described above, the thirdexposed part 101 and the fourth exposed part 102 are contiguous witheach other. This makes it easier to form the third exposed part 101,which is used for positioning the heat dissipation sheet 61, and thefourth exposed part 102, which is to be brought into contact with theextended heat dissipation sheet 61.

Third Embodiment

Hereinafter, a third embodiment will be described with reference to FIG.6. FIG. 6 is a perspective view schematically showing the heatdissipation sheet 61 of the third embodiment. As shown in FIG. 6, theholes 71 of the third embodiment include multiple recesses 110, multiplefirst cut-off parts 111, and multiple second cut-off parts 112 inaddition to the through hole 72.

The multiple recesses 110 are closed holes that are recessed from atleast one of the first contact surface 65 and the second contact surface66. In other words, the recess 110 opens at at least one of the firstcontact surface 65 and the second contact surface 66. The part that isformed with the recess 110 is thinner than the other part in the heatdissipation sheet 61.

The heat dissipation sheet 61 also includes an inside surface 115 and abottom surface 116 that form the recess 110. The inside surface 115faces the inside of the recess 110 in the direction along the outsidesurface 25 b of the bottom wall 25. In FIG. 6, the inside surface 115faces approximately the X direction or the Y direction. A part of theinside surface 115 and another part of the inside surface 115 face eachother. The bottom surface 116 is positioned at an inner part of the heatdissipation sheet 61 and faces the outside of the heat dissipation sheet61. The bottom surface 116 faces the Z direction in FIG. 6.

Each of the first cut-off part 111 and the second cut-off part 112 opensto the side surface 67. In other words, each of the first cut-off part111 and the second cut-off part 112 is recessed from the side surface 67to the inside of the heat dissipation sheet 61.

The first cut-off part 111 extends approximately in the Z direction andpenetrates through the heat dissipation sheet 61 between the firstcontact surface 65 and the second contact surface 66. That is, the firstcut-off part 111 opens to the first contact surface 65, the secondcontact surface 66, and the side surface 67.

The heat dissipation sheet 61 further includes an inside surface 117that forms the first cut-off part 111. The inside surface 117 faces theinside of the first cut-off part 111 in the direction along the outsidesurface 25 b of the bottom wall 25. A part of the inside surface 117 andanother part of the inside surface 117 face each other. Moreover, a partof the inside surface 117 faces the outside of the heat dissipationsheet 61 via an open end of the first cut-off part 111 of the sidesurface 67.

The second cut-off part 112 is recessed approximately in the Z directionfrom either one of the first contact surface 65 or the second contactsurface 66. That is, the second cut-off part 112 opens to either one ofthe first contact surface 65 or the second contact surface 66 and to theside surface 67.

The heat dissipation sheet 61 further includes an inside surface 118 anda bottom surface 119 that form the second cut-off part 112. The insidesurface 118 faces the inside of the second cut-off part 112 in thedirection along the outside surface 25 b of the bottom wall 25. A partof the inside surface 118 and another part of the inside surface 118face each other. Moreover, a part of the inside surface 118 faces theoutside of the heat dissipation sheet 61 via an open end of the secondcut-off part 112 of the side surface 67. The bottom surface 119 ispositioned at an inner part of the heat dissipation sheet 61 and facesthe outside of the heat dissipation sheet 61. The bottom surface 119faces the Z direction in FIG. 6.

The part that is provided with the through hole 72 or the first cut-offpart 111 is more easily deformed than the part that is provided with therecess 110 or the second cut-off part 112 in the heat dissipation sheet61. The through hole 72 and the first cut-off part 111 are closer to thescrew 55 than the recess 110 and the second cut-off part 112. Thepositions of the through hole 72, the recess 110, the first cut-off part111, and the second cut-off part 112 are not limited to these examples.

In the example in FIG. 6, each of the through hole 72, the recess 110,the first cut-off part 111, and the second cut-off part 112 has anapproximately square cross section orthogonal to the Z direction.However, each of the through hole 72, the recess 110, the first cut-offpart 111, and the second cut-off part 112 may have a cross section ofanother shape, such as circle.

In the HDD 10 of the third embodiment described above, the heatdissipation sheet 61 includes the surface 62. The holes 71 include therecess 110 that is recessed from the surface 62. This reduces decreasein volume of the heat dissipation sheet 61 due to formation of the hole71, thereby preventing reduction in amount of heat that can be stored bythe heat dissipation sheet 61. Thus, decrease in heat dissipationperformance of the heat dissipation sheet 61 with respect to thecontroller 58 is suppressed.

The holes 71 include at least one recess 110 that is recessed from atleast one of the first contact surface 65 and the second contact surface66. In this case, the reaction force acting from the first contactsurface 65 to the controller 58 is more distributed at the first contactsurface 65, and the reaction force acting from the second contactsurface 66 to the outside surface 25 b is more distributed at the secondcontact surface 66, compared with a case in which the recess 110 isrecessed from the surface 62 of the heat dissipation sheet 61 in thedirection along the outside surface 25 b. Moreover, the heat dissipationsheet 61 that is provided with the hole 71 is easier to be manufactured.

The heat dissipation sheet 61 includes the side surface 67 that isprovided between the first contact surface 65 and the second contactsurface 66. The holes 71 include the first cut-off part 111 and thesecond cut-off part 112 that open to the side surface 67. That is, thehole 71 that opens to the outside makes it easier for the heatdissipation sheet 61 to be deformed in such a manner as to extend in thedirection along the outside surface 25 b. Thus, the compressed heatdissipation sheet 61 is more easily deformed, and this reduces thereaction forces acting from the compressed heat dissipation sheet 61 tothe controller 58 and the PCB 51 and to the case 11. Moreover, gas thatis thermally expanded inside the hole 71 can be released to the outsideof the heat dissipation sheet 61.

In one example, multiple shallow recesses 110 may be provided in theheat dissipation sheet 61 by embossing. Providing such recesses 110 alsoincreases parts that are able to be deformed and be extended in the heatdissipation sheet 61, compared with a case of not providing the hole 71.Thus, the compressed heat dissipation sheet 61 is more easily deformed,and this reduces the reaction forces acting from the compressed heatdissipation sheet 61 to the controller 58 and the PCB 51 and to the case11.

FIG. 7 is a plan view schematically showing the bottom wall 25, thecontroller 58, and the heat dissipation sheet 61 according to a firstmodification example of the third embodiment. As shown in FIG. 7, eachof the first cut-off part 111 and the second cut-off part 112 mayinclude an approximately rectangular cross section orthogonal to the Zdirection.

FIG. 8 is a plan view schematically showing the bottom wall 25, thecontroller 58, and the heat dissipation sheet 61 according to a secondmodification example of the third embodiment. As shown in FIG. 8, eachof the first cut-off part 111 and the second cut-off part 112 mayinclude an approximately semicircular cross section orthogonal to the Zdirection. In other words, each of the first cut-off part 111 and thesecond cut-off part 112 may include a circular arc-shaped part.

As in these multiple embodiments, the holes 71 may include the throughhole 72, the recess 110, the first cut-off part 111 and the secondcut-off part 112. The holes 71 may further include a groove, a slit, ahollow, an opening, and a hole that is represented by other expression.

In at least one of the embodiments described above, the heat conductionmember is compressed between the electronic component and the outsidesurface of the case and thermally couples the electronic component tothe case. The compressed heat conduction member is deformed and extendsin the direction along the outside surface of the case between theelectronic component and the case. The heat conduction member isprovided with the hole. In response to compression of the heatconduction member, the outside edge part of the heat conduction memberis protruded outwardly, and the inside edge part of the heat conductionmember, which forms the hole, is protruded inwardly. In this case, partsthat are able to be deformed and be extended increase in the heatconduction member, compared with a case of not providing the hole. Thus,the compressed heat conduction member is more easily deformed, and thisreduces the reaction forces acting from the compressed heat conductionmember to the electronic component and the board and to the case. Whenthe reaction forces acting on the electronic component and the board andon the case are great, there is a risk that the board and the case willbecome deformed in such a manner as to be warped and stresses at acoupled part of the electronic component and the board will increase. Onthe other hand, in the disk drive of the embodiments of the presentdisclosure, the reaction forces are reduced as described above, and thisenables reducing deformation of the board and the case and preventingincrease in stress at the coupled part of the electronic component andthe board.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A disk drive, comprising: a case having an outersurface; a recording medium disposed inside the case and having arecording layer; a magnetic head disposed inside the case and configuredto read and write information from and to the recording medium; a boarddisposed outside the case, having a mounting surface that faces theouter surface, and electrically connected to the magnetic head; anelectronic component mounted on the mounting surface; and a heatconduction member having a hole and compressed between the electroniccomponent and the outer surface in a thickness direction of the diskdrive to thermally couple the electronic component to the case.
 2. Thedisk drive according to claim 1, wherein the hole penetrates through theheat conduction member in the thickness direction.
 3. The disk driveaccording to claim 2, wherein the heat conduction member includes afirst contact surface in contact with the electronic component and asecond contact surface in contact with the outer surface, and the holepenetrates through the heat conduction member and extends between thefirst contact surface and the second contact surface.
 4. The disk driveaccording to claim 1, wherein the hole is recessed from a surface of theheat conduction member that faces one of the electronic component andthe outer surface and does not penetrate entirely through the heatconduction member in the thickness direction.
 5. The disk driveaccording to claim 4, wherein the surface includes one of a firstcontact surface in contact with the electronic component and a secondcontact surface in contact with the outside surface.
 6. The disk driveaccording to claim 5, wherein the heat conduction member includes a sidesurface between the first contact surface and the second contactsurface, and the hole extends to the side surface.
 7. The disk driveaccording to claim 1, wherein the electronic component includes a facingsurface that faces the outer surface, the heat conduction memberincludes a first contact surface in contact with the facing surface anda second contact surface in contact with the outer surface, and thefirst contact surface is smaller than the facing surface.
 8. The diskdrive according to claim 7, further comprising: multiple mountingmembers for mounting the board to the case, wherein the heat conductionmember has one or more additional holes, and a first hole of which iscloser to the mounting member than a second hole and is larger than thesecond hole.
 9. The disk drive according to claim 1, wherein the holehas a circular cross section.
 10. The disk drive according claim 1,wherein the hole has a polygonal cross section.
 11. The disk driveaccording to claim 1, wherein the case is formed of metal and the outersurface includes a coated part and an exposed part that is enclosed bythe coated part, the metal being exposed at the exposed part, and theheat conduction member includes a contact surface in contact with theexposed part.
 12. The disk drive according to claim 11, wherein theexposed part includes an inner exposed part and an outer exposed part,the inner exposed part including a first edge that extends along anoutside edge of the contact surface of the heat conduction member beforeit has been compressed between the electronic component and the outersurface, and the outer exposed part including a second edge that isseparated from the outside edge of the contact surface of the heatconduction member before it has been compressed between the electroniccomponent and the outer surface and extends along the outside edge ofthe contact surface of the heat conduction member when it is compressedbetween the electronic component and the outer surface.
 13. The diskdrive according to claim 12, wherein the inner exposed part and theouter exposed part are separated by a region at which the metal is notexposed.
 14. A disk drive, comprising: a case having an outer surface; arecording medium disposed inside the case and having a recording layer;a magnetic head disposed inside the case and configured to read andwrite information from and to the recording medium; a board disposedoutside the case, having a mounting surface that faces the outersurface, and electrically connected to the magnetic head; an electroniccomponent mounted on the mounting surface; and a heat conduction memberbetween the electronic component and the outside surface in a thicknessdirection of the disk drive, the heat conduction member including afirst contact surface in contact with the electronic component and asecond contact surface in contact with the outside surface, and having ahole that opens to at least one of the first contact surface and thesecond contact surface.
 15. The disk drive according to claim 14,wherein the hole opens to both the first contact surface and the secondcontact surface.
 16. The disk drive according to claim 14, wherein thehole is recessed from one of the first contact surface and the secondcontact surface.
 17. The disk drive according to claim 16, wherein theheat conduction member includes a side surface between the first contactsurface and the second contact surface, and the hole extends to the sidesurface.
 18. The disk drive according to claim 14, wherein theelectronic component includes a facing surface that faces the outersurface, and the first contact surface is smaller than the facingsurface.
 19. The disk drive according to claim 14, wherein the hole hasa circular cross section.
 20. The disk drive according claim 14, whereinthe hole has a polygonal cross section.